Instrument maker:Laurent Cassegrain

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Name: Laurent Cassegrain

Birth: around 1629

Birthplace: Chartres,France

 

 

Today is the anniversary of the Birth of the French Catholic priest and instrument maker Laurent Cassegrain. Although this image may be a likeness of Laurent Cassegrain, no verifiable portrait of him is known to exist.


he is best known to astronomers as being the probable inventor of a type of reflecting telescope which uses a combination of a primary concave mirror and a secondary convex mirror. 


Now known as the Cassegrain reflector, Cassegrain’s design first appeared in the 25 Apr 1672 issue (pictured) of Le Journal des Sçavans (established by French writer Denis de Sallo in 1665 and the earliest academic journal published in Europe). 


The 55 km diameter lunar crater Cassegrain, located to the south east of the larger crater Lebedev on the far side of the Moon and seen here immediately to the lower right of image centre, is named in his honour.

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